Mode of obtaining curved printing-surfaces



UNITED STATES PATENT OFFICE.

IVM. H. ELLIOT, OF PLATTSBURG, NE\V YORK.

MODE OF OBTAINING CURVED PRINTING-SURFACES.

Specification of Letters Patent No, 23,236, dated March 15, 1859.

To all whom it may concern:

l follows: Take the flexible sheet and lay it Be it known that I, IVM. II. ELLio'r, of i upon a fiat surface and spread upon it a Ilattsburg, county of Clinton, and State of New York, have invented a new and Improved Method of Making Curved Printing- Surfaces;I and I do hereby declare that the following isa full and exact description of the same, reference being had to the accompanying drawings and the letters of reference marked thereon.

The same letters of reference indicate the same parts in each figure.

The nature of my invention consists in the construction of a` curved or cylindrical mold for casting curved stereotype plates to be used upon cylinder presses, and in a peculiar method of producing an exact cylindrical curve in a flexible matrix previous to depositingl or casting metal upon it.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

Figure l, is a perspective view of my curved mold. Fig. 2, is a vertical cross section of the same. Fig. 3, is a vertical longitudinal section of the mold. Fig. al., is a perspective view of the compound flexible impression sheet or matrix. Fig. 5, is a horizontal section of my curved mold.

fz, concave cylindrical form, or outer shell of the mold, Z) the inner or convex shell of the mold, c flexible sheet, (Zybars across the ends of the flexible sheet which serves the double purpose of receiving` the force of the screws 7c, and transmitting` the same equally to all parts of the sheet, and at the same `time they form the ends to the mold when placed between the outer and inner shell, c composition spread upon the fiexible sheet in which the impression is made, and which when made serves as a matrix for casting` the face of the type, f screw-plug to stop sprue it", in the inner shell, g support across the top of the outer shell fastened by screws i, It supportacross the inner shell and fastened by screws n, Z2 screws passing through support g and pressing upon bars CZ, i," screws passing through support g and pressing upon support 7i for the purpose of holding the outer and inner shell together, d curved bar attached to the outer shell and forming one side of the mold, d curved bar attached to the inner shell and forming the other side of the mold.

The process of producing a curved printing surface by this mold and matrix is as silicions composition possessing the following qualities, viz: it must be capable of receiving the impression of the type and of being removed from the type while it is yet soft enough to be bent into the curved form, and after it is bent into the required shape, it must be capable of drying without cracking, and of receiving the melted metal upon it without alteration. These qualities are found in a great degree in the following composition, viz, clay five parts, gypsum five parts, calcium, chalk and silexeach two parts, and starch one part. To spread this mixture upon the sheet, it is necessary to puton at first more than is required, and then by means of a gage to strike olf all but about a sixteenth of an inch in thickness over the whole surface of the sheet. The sheet then laid upon a flat press and th-e type pressed into the composition till they come in Contact with the sheet itself, o1` with a sheet of paper cemented upon the exible sheet, to protect the type, and after remaining a few minutes to give the composition time to set a little, the type are removed by raising them perpendicularly and holding down the ends of the sheet, when the separation commences at the ends, and proceeds toward the center. In this way the type are removed from the composition without destroying the correctness of the impression or matrix thus formed. This device being composed of a flexible. sheet c, and a coating of impressible material or composition, c, I call my compound flexible matrix. The matrix is then taken and bent into about the required curve and placed in the concave cylindrical form or outer shell of the mold a, and when properly adjusted the force of screws f may be brought to bear upon bars (Z, the effect of which is to cause the flexible matrix to assume the exact form of shell o. This method of bringing the flexible impression sheet or matrix to the required form and holding it there has been found perfectly practicable and reliable, both for depositing metal upon, as in making electrotypes, and for casting metal upon, as in making stereotypes. After the matrix has been secured in the form, the inner shell is placed over it and fastened in its place by screws 7c. The mold is then 'usual method of making fiat stereotypes,

and When it is ready to be removed and cooled, the sprue f must be closed by screw plug Around the inner or convex shell deep grooves m, m, are formed. In these flanges are cast upon the inner or concave side of the stereotype plate. These flanges lit into corresponding depressions in the printing cylinder, and pins or keys are passed through them to fasten them upon the cylinder.

For making curved stereotypes the concave form shouldbe enameled, and afterward ground to a perfect circle; this enameling will prevent the metal from being deposited upon the form While in the battery, or under its influence.

It is not necessary that the sides a and c should be attached as before specied, one to the outer and one to the inner shell; they may both be attached to one shell or be entirely separate from the shells, nor need the ends (IZ be attached to the tlexible sheet. These ends 'may be attached to the inner shell, or the sides and ends of the molds may be made in the form of a convex frame fitting between the outer and inner shells, and so be independent of all'the other devices. The support g, may also be movable, and the matrix be let down into the outer shell from the top instead of being pushed in at the end.

I do not intend to limit myself to any particular method of making up the mold or to any particular material for receiving the impression, neither do I limit myself to any particular device for producing pressure upon the ends of the sheet, a. Wedge or lever would be equally as good as screws 7u, and

the result would be the same.

The bars d, when firmly secured resist any tendency the flexible sheet may have, by reason of its elasticity, to spring up and displace itself from the face of the outer' shell a. The sides (Z/ and c being non-flexible or nearly so and permanently curved to the required cylindrical form, and resting as represented in the drawings upon the flexible sheet outside of the impression or matrix serve to confine it closely to the concave form a, thus giving to the compound flexible matrix the required curve.

I do not claim casting stereotypes by immersion in molds formed upon and-adhering to metallic plates, nor do I `claim a compound ilexible matrix for casting curved stereotypes as thatis the subject of an English patent granted to Brunel in 1820. But

Vhat I have invented and Wish to `have secured to me by Letters Patent, is-

1. The combination of screws k, with the concave cylindrical form a', when these devices are used for bringing the compound flexible matrix or impression sheet, to the required shape or for holding it there While metal is beingdeposited or cast upon it, for the purpose of constructing electrot-ypes or stereotypes, as specified.

2. The employment of bars (l, in combinat-ion With the vflexible sheet c, for holding the matrix in a cylindrical form, Whe-n said bars are so applied to the ends of said sheet, that they shall prevent'its bein-g displaced, or springing up, from the concave face of the outer' shell, a, as setforth, Whether' said bars are attached to, or rest against the edge of said sheet.

The grooves M, M, in the inner shell Z), for casting upon the back of cylindrical type plates, lugs or flanges by which said plates may be fastened upon a cylinder as and for the purpose set forth.

IVILLIAM 'H. ELLIOT.

IVitnesses Jas. H. CARTER, C. HALSEY. 

